I think the back wave of the OB (dipole) has a lot to do with how the "soundstage" picture gets re-created. A bipole (rear emission in same phase as front - like a speaker pointed up, perhaps with a radial reflector above it) doesnt do it in quite the same way - for me.
So hooray for out-of-phase sound emissions coming from the rear of the speaker!
If that works for you too, put it with any sound being reflected back through the cone from relatively close cabinet walls being mostly eliminated and you can see the advantage part of the "tradeoff stack" of the OB design. The bass tradeoff stinks, but it can be mitigated as has been done in many, many ways.
So hooray for out-of-phase sound emissions coming from the rear of the speaker!
If that works for you too, put it with any sound being reflected back through the cone from relatively close cabinet walls being mostly eliminated and you can see the advantage part of the "tradeoff stack" of the OB design. The bass tradeoff stinks, but it can be mitigated as has been done in many, many ways.
There is no harm adding nice tweeter. Sound may improve even further if you eliminate those breakup peaks. No one said it has to remain single speaker.
This would be alternative option for new full range. Perhaps even better.
This would be alternative option for new full range. Perhaps even better.
No one said the rear wave has to be full range; fawk the rear wave can no tweeter information for the dipole soundstage illusion to form.
I for one certainly havent gone as far as to add a front firing tweeter and a rear one, albeit out of phase. I think XRK's latest OB build has a tweeter that's dipole, along with the mid. I wonder how that works out tweeter-dipole wise?
Is there any highs on the back side off a fullrange driver? No whizzer cone for example and more or less closed structure creating acoustic low pass.
edit. remembered I had full polars measured of naked 8" mid driver. It is not particularly a fullrange driver, and has quite a closed back. Goes south from 2kHz up, although the hash ~10kHz stays roughly the same. Not sure if that is already some background noise or what. Anyway, would be interesting to see if anyone has measurements of their naked drivers 😉
Whole thing rotated, interesting. DI shows the system is going omni on the back past few kHz. Quite a nasty response all around, some of it is from the rig.
edit. remembered I had full polars measured of naked 8" mid driver. It is not particularly a fullrange driver, and has quite a closed back. Goes south from 2kHz up, although the hash ~10kHz stays roughly the same. Not sure if that is already some background noise or what. Anyway, would be interesting to see if anyone has measurements of their naked drivers 😉
Whole thing rotated, interesting. DI shows the system is going omni on the back past few kHz. Quite a nasty response all around, some of it is from the rig.
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X is not the only one using dipole tweeters, its a common thing...from cheap grs to expensive raal
https://www.madisoundspeakerstore.com/cart2/ribbon-tweeters/raal-dipole-140-15d-ribbon-driver/
True. On of my favorite speaker builds was with 15" woofers on OB with Altec 811 horns as the mid & high. Wonderful, I miss them.
Inspired by Linkwitz I did experiment with rear firing tweeters and they were "OK" but needed a lot more level than I expected.
Just spent another couple of hours listening, they're great fun 🙂
Thank you! I think I will enjoy them indeed. Yeah, the lack of bass was something I immediately noticed, but it really doesn't bother me that much. I'm not going to spend much more time on the filtering of the full range driver. I am currently using a notch filter (5,6 uF + 0,56 mH using a 2,2 Ohm bypass resistor - just stuff I had laying around) and I'm happy with how the full range driver is performing now!
Thank you! I do plan on finishing them off with some woodstain and there's a lot of sanding to do, but I'm too busy listening at the moment... Front loaded horns look amazing. Don't think my girlfriend would like me going even crazier though. Next thing on my list: find myself an affordable tube amp...
The fact that there are no other forces exerted on the cone (i.e. no backpressure) is what impressed me the most. That's what gives an OB that sense of effortlessness I think. I haven't given them enough room to really breathe yet though. With these, placement is everything. They need toe in and you want to be right in the center of the whizzer cone "beam" for them to sound lively.
Yeah, I'm with you on this one. I heard some omnidirectional speakers before but wasn't impressed. The main benefit of those appears to be a way wider sweetspot. But meh..
I'm currently looking at adding a small ribbon / AMT tweeter with a first order crossover (single low uF cap) to augment the highs.
I am not so sure about this. I think the dipole effect is mostly coming from the lower frequencies reflecting through the room, but since ambient tweeters or rear mounted tweeters appear to be a thing, I wouldn't know until I try.
I recently saw a marketplace listing from somebody selling their Altec Lansing horns due to permanent hearing damage from "enjoying them too much"... 🤐
Ha ha! Good one. They sure can get loud, but they don't have to.
With my OBs topped with Altec 811s we were watching the TV series The Sopranos on DVD on our first 32" flat screen television. The sound was so big, clear and detailed that it just didn't fit well with the little TV. The image seemed puny and lack luster in comparison. The image was DVD but the sound was 4K. 🙂
There is (or was?) very nice planar/ribbon fostex on parts express on sale, cheap but perfectly perfoming, used it trice. Easy to use with 2uF up, goes flat to 30kHz.
https://www.parts-express.com/Foster-E100T10-Ribbon-Tweeter-8-Ohm-279-468
https://www.parts-express.com/Foster-E100T10-Ribbon-Tweeter-8-Ohm-279-468
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Pano, you are absolutely right, sound and image have to keep up with each other. I use hd projector.
Most of the time, its other way around, nice oled tv, crappy sound. You cant enjoy movies that way either.
Most of the time, its other way around, nice oled tv, crappy sound. You cant enjoy movies that way either.
I actually just put together some very basic/ugly OBs last week and after some crude eq with my mini dsp they're sounding wonderful. Faitalpro 15" and a cheapo 8" wide ranger on a large baffle coupled to the side wall, very much Gilbert Briggs style.
Nice! I used to watch movies and series on an old small 32" LG TV from the late 00s. Sound was coming through an NAD C350 to homemade MLTL speakers. Immense sound but disappointing image. Still a fun experience.
Oof, I live in the Netherlands... Those tweeters are exactly what I would be looking for but shipping and import tax would do my head in. I've been looking for those (Foster E100T10 Planar Tweeter) but they aren't available in the Netherlands.
I've also been looking at cheaper compression driver horn tweeters. Would look amazing mounted to the top of the baffle 😀 They would only be used above ~10K or something.
Soundstage and imaging from OB setups has “irreversibly” spoiled me and permanently raised my expectations for any setup. I have played with single full range drivers mounted on moderately large L shaped open baffles and it also helped me voicing my different tube amps too. I did measure one of my FRs on these very baffles: (at my listening position)
I am pretty sure that that is what i don’t like about OBs. I have built many, abandoned them all, the issue they have gets in my head and makes them not so enjoyable.
I do have one more coming (i have 8 dedicated OB woofers that need using).
dave
I know you dont like them. That's why I'm a bit careful to explicitly say "for me". It's good to have a diversification of opinion from a top speaker designer, lest us more pedestrian aficionados get swept away in the OB hype, or, at least get an expectation bias setup by it.
For my next hallucinatory trick, I'm going to try Polk SDA'ing with a set of 4 JBL HLS speakers. If that illusion pans out in a supplementary way soundfield wise, I'm going to try it on a couple OB 20" by 20" panels with 4 MA drivers; two on each panel.
I wonder what the back wave of a horizontally arranged pair - with one carrying out of phase info from the opposite channel - would result in? Of course, 200 Hz on up for the panels and then perhaps rolling off at 2k for the "hallucination engine" driver. Perhaps that one wants a small, sealed enclosure?
Should at least be fun to try.
When I heard some designs with helper tweeters at an audio show I was't really impressed, it didnt seem to change that much. The best sense of space, 3D soundstage and "live" sound was from an omni speaker. I think it had both woofer and tweeter fire at the same reflection disk, woofer was firing upwards and worked in a closed, tapered box. It was really something special, beating even much more expensive and exotic setups. Very much OB sound with actual bass extension.
That's very cool! I feel like these DEW drivers are so wrong when it comes to accurate reproduction yet they are so immersive. I too have now been irreversibly spoiled I'm afraid.
To each their own of course. I'd never claim this is "audio nirvana" or something, it's just something different and fun for me. I might dabble around in the dipole realm for a while.
This sounds very interesting. Would you happen to have any pictures or a brand name / designer or creator?